Dataflow question

Dataflow question

[Rask Ingemann Lambertsen]

   I have a simple loop over the defs of an INSN, looking for the def of a
specific register X:

  struct df_ref **defs;
  for (defs = DF_INSN_DEFS (insn);
       *defs && !rtx_equal_p (DF_REF_REG (*defs), x);
       defs++)
    ;

   It doesn't work because the modes don't match:

(gdb) call debug_rtx (defs[0]->insn)
(insn 9 8 10 2 /tmp/pr3507-3.c:9 (set (reg:CCSO 13 cc)
        (compare:CCSO (reg/v:HI 22 [ a ])
            (reg/v:HI 23 [ b ]))) 269 {*cmphi_ccso} (nil))
(gdb) call debug_rtx (defs[0]->reg)
(reg:CC 13 cc)

   Should I just compare register numbers instead?

-- 
Rask Ingemann Lambertsen
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Re: Dataflow question

[Paolo Bonzini]

Rask Ingemann Lambertsen wrote:
>    I have a simple loop over the defs of an INSN, looking for the def of a
> specific register X:
>
>    Should I just compare register numbers instead?

I think so, or maybe even use reg_overlap_mentioned_p.  It depends what 
you're doing.  For 4.4, it may be worth modifying df_find_def and 
df_find_use so that you can just use those.

Paolo